Seven Palestinian civilians were killed and dozens were injured when artillery shells fired by the Israel Defense Forces exploded on a beach north of the Gaza Strip on Friday, Palestinian Health Minister Basem Naim said.

Initial reports had it that the shells were fired by the navy, but an initial military investigation into the incident revealed that the shells were fired from land canons. At least 30 people were injured in the attack, Palestinian sources said.

Injured Palestinian girl taken to hospital (Photo: AP)

Israel frequently shells launch pads in the Gaza Strip used by gunmen to fire Qassam rockets at Israel.

Among the victims are two women, one of whom lost both her children, a one-year-old toddler and his three-year-old sister. Dozens others were injured in the attack, which occurred on busy Gaza beach near Beit Lahiya.

Israel Defense Forces Chief of General Staff Lit.-Gen. Dan Halutz ordered a halt to all artillery fire until the circumstances of the deadly incident become clear.

Abbas condemns 'Israeli massacre'

Palestinian President Mahmoud Abbas condemned the incident as an Israeli "bloody massacre" and declared a three-day mourning period

.

Abbas said embassies around the world would be closed and flags would fly at half staff.

"No doubt what's going on in Gaza is a bloody massacre against our people, our civilians, without

discrimination," he said. "I call upon the international community, Security Council, the Quartet, to put an end to this Israeli killing policy."

IAF steps up air strikes

Shortly after, medical sources said three Islamic Jihad activists were injured by a missile that hit their car in Beit Lahiya in an apparent Israeli air strike. The army said the men had planned to launch rockets at Israel.

Earlier, two Palestinians were killed in an Israeli air strike in the northern Gaza Strip. A missile fired by an Israeli helicopter slammed into a car traveling in Beit Lahiya, killing senior amas commander Mohammad Abu Sahila and his companion, Ahmad Siam.

Palestinian girl wails by body of family members (Photo: AFP)

Earlier Friday, three Palestinians were killed in an air strike that targeted a car carrying three members of the Popular Resistance Committees who launched a Qassam rocket at Israel.

Top Fugitive Killed

Rafah: 30,000 attend Samhadana's funeral / Ali Waked

Thousands of Palestinians arrive in Gaza to take part in funeral, special prayer in honor of Popular Resistance Committees chief assassinated by IDF Thursday; Islamic Jihad official confirms: Samhadana killed while planning terror attack

The Israel Defense Forces said it attacked the Qassam cell after its members fired a rocket into Israel, lightly wounding one man. A second airstrike then hit the car carrying the cell members as they tried to speed away, killing the three men, the army said.

Palestinian officials, however, said the airstrikes had targeted separate groups several miles apart

from one another.

There were no reports of injuries or damage caused by the Palestinian rocket.

The killed Palestinians were identified as Basel Zaanin, his brother Ahmad and Khaled Zaanin, a relative.

On Thursday night, the Israel Defense Forces killed Jamal Abu Samhadana, the man in charge of one of the strongest terror organizations in Gaza, who was appointed as the general supervisor of the Interior Ministry, the ministry responsible for the security organizations.

An aircraft fired four missiles on one of the organization's training camps. At least four people were killed in a strike planned by the Southern Command and the Israel Air Force, which considered Samhadana to be one of the most wanted Palestinians. He had escaped at least four assassination attempts and has been wanted since the first intifada.

Some 30,000 Palestinians arrived in the Gaza town of Rafah Friday afternoon to attend the funeral of Popular Resistance Committees chief Jamal Abu Samhadana.

At the end of the funeral, a special prayer was expected to be held at the local soccer field. Dozens of gunmen deployed across the city ahead of the funeral.

A Popular Resistance Committees spokesman said during the funeral that the organization has elected a new secretary-general. He added that the organization would not publish the replacement's name "for security reasons."